Arctic sea ice extent at a record low for the time of the year

Record
Arctic Warming

For
more on what constitutes "ice-covered" and what is sea ice
extent (versus sea ice area), see this NSIDC FAQ
page.

Another
measure is sea ice area. On April 2nd, 2016, Northern Hemisphere sea
ice area was at a record low for the time of the year, reports
the Cryosphere
Today.

In
2015, there still was more sea ice area than there is now when it
was half a month later (15 days) into the year. In 2012, there still
was more sea ice when it was 25 days later in the year. In other
words, sea ice area decline is almost one month ahead compared with
the situation in 2012.

NSIDC scientist Andrew Slater (see his
website)
has created the chart below of freezing degree days in 2016 compared
to other years at Latitude 80°N.

The
Arctic has warmed more than elsewhere on Earth. Surface temperatures
over the past 365 days were more than 2.5°C or 4.5°F higher than
they were in 1981-2010.

The
image below compares sea ice thickness on April 3rd for the years
2012, 2015 and 2016 (respectively the left, center and right panel).

[
click on images to enlarge them ]

This
means that the outlook for the sea ice in the Arctic this year is
not good. Given that the current El Niño is still going strong
and given the currently very high ocean temperatures, chances are
that the sea ice will be largely gone by September 2016. The image
on the right shows sea surface temperature anomalies above Latitude
60°N.

Sea ice acts as a buffer, absorbing heat and keeping
the temperature of the water at freezing point. Without such a
buffer, further heat will instead make that the temperature of the
water will rise rapidly. Furthermore, less sea ice means that less
sunlight gets reflected back into space and more sunlight instead
gets absorbed by the Arctic Ocean.

These are just some of the
many feedbacks that
accelerate warming in the Arctic. Warm water reaching the seafloor
of the Arctic Ocean can penetrate sediments that can contain huge
amounts of methane in the form of hydrates and free gas, triggering
abrupt release of methane in gigantic quantities, escalating into
runaway warming, and subsequent destruction and extinction at
massive scale.

The situation is dire and calls for
comprehensive and effective action as described at the Climate
Plan.